The herbarium specimens of Diospyros (including type specimens, or digital images) conserved at BK, BKF, K, L, and P were studied.

On the basis of expansive molecular phylogenetic analyses of the genus Miliusa (Annonaceae) utilising up to seven plastid DNA regions, four major clades are identified: clades A, B, C and D. Members of clade C possess axillary inflorescences and crescent-shaped to semicircular glandular structures at the base or (slightly) higher inside the inner petals. In this clade, accessions of M. mollis are recovered as a monophyletic group, divided into two major clades. One of them is recognised as a new species, M. microphylla, which differs from the other (M. mollis) in the following characters: pedicel length, as well as glandular structures and indumentum on the inner petals. The new species is endemic to southeastern Thailand, whereas M. mollis has a much wider distribution (central, eastern, northeastern, northern and peninsular Thailand plus Cambodia and Vietnam). In addition, M. glandulifera, a new record for Thailand, is retrieved as the sister group of a clade composed of M. microphylla and M. mollis. The name M. glandulifera is lectotypified and the description of M. glandulifera is emended, with the information on mature monocarps added. The conservation status of M. microphylla and M. glandulifera is provisionally assessed. A revised key to the species in clade C in Thailand is provided. The phylogenetic position of M. nakhonsiana and M. sessilis in clade C, as well as of M. chantaburiana and M. eupoda in clade B is confirmed for the first time.

In 2000, we established a 24-ha plot in Peninsular Thailand to investigate how forest composition, structure and dynamics vary with spatial heterogeneity in resource availability. Detailed soil and topographic surveys were used to describe four edaphic habitats in the plot. Disturbance history was inferred from historical records and floristic analysis. The plot included >119 000 trees ≥1 cm dbh in 578 species, and was recensused in 2010. Species distributions, floristic turnover, stand structure, demographic rates and biomass dynamics were strongly influenced by heterogeneity in soils, topography and disturbance history. Over 75% of species were aggregated on specific edaphic habitats leading to strong compositional turnover across the plot. Soil chemistry more strongly affected species turnover than topography. Forest with high biomass and slow dynamics occurred on well-drained, low fertility ridges. The distribution and size structure of pioneer species reflected habitat-specific differences in disturbance history. Overall, above-ground biomass (AGB) increased by 0.64 Mg ha−1 y−1, from 385 to 392 Mg ha−1, an increase that was entirely attributable to recovery after natural disturbance. Forest composition and stand structure, by reflecting local disturbance history, provide insights into the likely drivers of AGB change in forests. Predicting future changes in tropical forests requires improved understanding of how soils and disturbance regulate forest dynamics.

We describe Lasianthus ranongensis Sinbumr. & Napiroon as a new species in the genus Lasianthus. The new taxon is intensively discussed through taxonomic affinities and information on its habitat, distribution and conservation status is provided. Moreover, line drawings and stereo microscope images of important fertile organs are demonstrated. The new species is morphologically similar to L. stipularis but differs in its having flattened branches (vs. terete), leaf blade elliptic-oblong shape of 15.0–20.0 × 4.0–6.0 cm (vs. oblanceolate-oblong 12.0–16.0 × 3.0–5.5 cm), 9–12 pairs of veins (vs. 9–10 pairs), stipule 5–7 mm long, half covering cymes (vs. 10–12.5 mm long, entirely covering cymes), four or five bracts narrowly lanceolate, 2.5–3.0 mm long (vs. bracts numerous, broadly triangular, 10–15 mm), flowers with cupular calyx (vs. with campanulate calyx), corolla villous on internal surface, and six or seven lobed (vs. pubescent on internal surface and four lobed) and drupes with five pyrenes (vs. with four pyrenes). It is also similar to L. pseudo-stipularis, but from which it is obviously distinguished by its stipule half covers cymes, secondary veins have 9–12 pairs of secondary veins, cupular calyx shape, six or seven lobed corolla, and drupe with five pyrenes, whereas L. pseudo-stipularis has stipule entirely covering cymes, 7–8 pairs of secondary veins, obconic calyx, four lobed corolla, and drupe with four pyrenes.

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